On the different descriptions of the non-Newtonian viscosity (shear-thinning effect) of glass melts with respect to heat dissipation

The range of non-Newtonian viscosity is usually connected with high strain rates or/and stresses. Thus, the effect of heat dissipation (or viscous heating) cannot be neglected. In previous papers, various correlations have been given to regard this effect. In the present paper, four different expressions of the normalized viscosities are theoretically discussed and experimentally demonstrated to show which expression reflects best the pure non-Newtonian behavior and the gross viscosity effect.